I don't understand how that could be too much work. You just click Visit, then click whatever a limited number of times a day.
I have 24 active citymates, if it becomes required/encouraged to visit each shop every day that's a significant amount of time. I don't think my city would add a requirement (we don't even have raid reqs) but I could see a lot of places adding rules about it and demanding daily visits.
How is it a good thing for them to ask for stuff you cannot make? Especially when you can't even ask for said item on Trade House or City Requests cause the item level is too high?
They should only ask for items within 3 levels of themselves, if your Fiora wants a level 38 item that probably means you've leveled her to 35+. You can also suggest items that are up to 7 levels lower than her current level, provided she can use that item type, so you could try stocking some items to suggest to her. Or the "buy from trade" button on the selling menu should let you access the item on trade, iirc? And after you've owned the item at least once it should be available in the regular tradehouse too. Or you could ignore/reject her until you catch up on which items you can craft, she won't mind waiting.
It sounds like you're still early-mid game, the way you manage your shop is different later on. My heroes don't get to choose what they buy. A majority are forced to buy goddess tears and gaia's essences, and the ones who can't will get junk from raid, failed precrafts, or rejected. Not all items are created equal, it's more profitable to craft what sells best and tell heroes to buy it, and with enough racks you can suggest and surcharge every single time. There are some items/qualities that are so valuable that I won't sell them to regular heroes, even if they ask I'll reject them and wait for an impatient. Impatients are the heroes with spiked bubbles and a timer, they pay double. Get one of those on a flawless gaia's essence and you get about 300m gold for a single item.
Now, suppose they only ask for items we can craft.
If my goal is to sell goddess tears (level 39), I need my level 35-45 heroes in the shop and level 40s for impatients. I've unlocked oodles of blueprints so my heroes would still ask for every item under the sun. Even if necklaces were trending, an impatient hero could ask for an ancient amulet (4m gold) or trine charm (2m) instead of that flawless tear (34m) because I've unlocked all the common blueprints. Not to mention dozens of other blueprints from other lines that are in their level range.
If a player doesn't like unlocking blueprints and their only level 40ish necklace is goddess tear, then those impatients are more likely to be for tears only. And they'd be more likely to get heroes requesting tears instead of junk in general, saving them energy on suggestions. It would give them a higher concentration of requests for things they actually want to sell because the request range would be narrower.
So in a shop like mine I would be punished for taking the time to unlock lots of blueprints (heroes would request everything) while those who don't unlock things would gain a significant advantage when it comes to what's requested since their heroes wouldn't ask for as many unprofitable items. That difference is why I'm against it, even if it's a little frustrating at lower levels or when you don't have enough hearts to suggest things yet.
On a related note, just because someone can
craft something doesn't mean they want to.
That's a level 27 great precraft, and the precraft has 2 good precrafts. For a measly 1m gold I'd still be telling Fiora to gtfo or buy something else. If you don't get requests for it, I don't want them either.